Henry County police are searching for a Christian author who has been missing since Thursday afternoon.

Henry Thomas Blackaby, the author of “Experiencing God” and other religious-oriented books, was last seen when he left his home in Rex, police said. Officials say he was driving a black 2010 Lincoln MKZ. They said the vehicle’s license plate is ATP6956.

Blackaby, 78, has type 2 diabetes, according to a website for Blackaby Ministries International. He is without insulin and may be disoriented.

The missing man’s credit card was used within six miles of his house.

“At this point we know very little,” said Rick Fisher, a vice president of Blackaby Ministries. “He was last seen at his home.”

Blackaby’s son Richard posted a message Friday on Twitter stating: “Please pray for Henry Blackaby. In need of prayer right now.”

In another post, he wrote: “Henry Blackaby update: As of 5 p.m. he has not been located. Police still searching. 100s of volunteers searching. Please continue to pray!”

Police have issued a Mattie’s Call, an emergency missing alert for disabled people and the elderly.

The Blackaby Ministries website identifies Blackaby as the founder and president emeritus of the organization. He and his wife, Marilynn, have previously served churches in California and Canada.

Anyone with information regarding Blackaby’s whereabouts is encouraged to call 911.